OBJECTIVES::  This study aims to estimate intravenous immunoglobulin (IVIg) costs (total cost/year and cost/patient/year) and treatment patterns of adult chronic immune thrombocytopenia (cITP) patients in the Brazilian Public Healthcare System (SUS), as well as general patient characteristics (age, gender). METHODS::  An observational retrospective cohort study was performed in DATASUS (public database). In order to estimate cost of IVIg/year/patient, an enrollment period from January 2012 to December 2013 with a follow up period until December 2015 was defined. ICD-10 code (D69.3) was used to identify patients (patients less than 18 years were excluded), which were followed up for 2 years in order to obtain an average cost of IVIg/year/patient with cITP. In a secondary analysis, total immunoglobulin cost related to cITP was estimated in each year (2012-2015). RESULTS::  : 660 patients were eligible in the defined enrollment period, 68% were women and the average age was 43 years. Of these, 590 used immunoglobulin, which accounted for 99% of the total cITP cost. Average cost per patient with IVIg was around R$16,000/year. Average annual immunoglobulin cost was R$57,200 for those patients that needed at least 3 immunoglobulin usages in a year, around 8% of the patients. Their expenses represented 30% of the total cost per year. The annual spending by the Ministry of Health for immunoglobulin use ranges from R$ 9.5 million (2012) to R$ 16.6 million (2016). CONCLUSIONS:

: IVIg acquisition represents a substantial cost for the Brazilian government. Patients with high frequency of immunoglobulin use represent a significant burden for SUS since IVIG is used mainly as rescue therapy and has a transitory efficacy. Therefore, this study suggests that there is a high unmet medical need in cITP patients for more efficacious treatments that could reduce the burden associated with immunoglobulin usage in the Public Health System.